D-sub connectors - Computer Definition

(D-SUBminiature connectors) A family of plugs and sockets widely used in communications and on earlier PCs. For example, the analog VGA monitor interface uses a D-sub 15-pin plug and socket. Also called "DB connectors" and "D-subs," they come in 9, 15, 25, 37 and 50 pin varieties. The D-sub designation defines the physical structure of the connector, not the purpose of each line.
Technically Not Always DB
In the international DIN 41625 standard, the letters A through E define the number of pins and follow the D. Although called "DB connectors," the only true DB is the DB-25, because B means 25 pins (see illustration below).
DB-25
The female DB-25 was widely used in the past for the printer port on a PC (see printer cable). The male DB-25 was also the second serial port (COM2) on the PC when serial ports were popular. It is still widely used for RS-232 communications devices.
DB-9 (DE-9)
The male DB-9 connector (officially DE-9) was typically used for the first serial port on earlier PCs (COM1) as well as other communications devices. See serial port.
DB-15 (DA-15 and DE-15)
Two DB-15 connectors are widely used. The larger, two-row female DA-15 is the game port on a PC, and the smaller, three-row, female high-density DE-15 is the VGA port. See VGA and plugs and sockets.